In order to identify each device such as a computer or a router that is connected to computer network in which IP is used, it is necessary to allocate a non-overlapping address to each device. The term device here means real devices such as personal computers or routers, or virtual devices established on computer program.
Conventionally, such an address is allocated through manual operation by a manager or the like. However, when the address is to be allocated through manual operation, there is problem that the manager is required to previously manage every address of every device and the manager or the user is required to set the address of each device such that it is different from the address of any other device. If by mistake, two devices are allocated with the same address, then collision of address disadvantageously occurs.
The above-mentioned problem maybe solved as follows. That is, a server which will automatically set non-overlapping addresses to each device on the network may be provided. This server may be made to previously store all the usable addresses, and it may be made to allocate a non-overlapping address in response to a request from a device. With this arrangement, non-overlapping addresses can be automatically and surely allocated to the devices. However, there is a drawback that workload increases because it is necessary to provide, maintain, and manage such a server.